"I violated team rules," Siverand says, "which would be unacceptable in normal times, but absolutely inexcusable now during a pandemic."
Siverand says he's apologized to Seahawks officials vehemently ... with ESPN reporting he even personally handwrote a sorry note to the team.
Siverand was an undrafted free agent cornerback who had a small chance of making Seattle's roster ... and now has an even smaller chance of catching on again in the NFL.
But, Kemah says he's learned from the incident ... and is vowing to do everything he can to sign with another team.
"I want to make sure this one mistake will not define me," the former Oklahoma State star said. "And I will continue training harder than ever to continue pursuing my dreams of playing in the National Football League."